SOLUTION: sin 3π/5 x cos 7π/30 + cos 3π/5 x sin 7π/30 = ?

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Question 921956: sin 3π/5 x cos 7π/30 + cos 3π/5 x sin 7π/30 = ?
Answer by srinivas.g(540) About Me  (Show Source):
You can put this solution on YOUR website!
RUle:
SIn A *cos B + cos A*Sin B = Sin( A+B)
so sin 3π/5 x cos 7π/30 + cos 3π/5 x sin 7π/30 = sin(3π/5+7π/30)
we need to simply the expression in the brackets i.e 3π/5+7π/30
multiply and divide with 30

(3π/5) *(30/30) + (7π/30)* (30/30)
= (3π/1)*(6/30)+(7π/30)*(1/1)
= 3*6π/30 +7π/30
= 18π/30 +7π/30
= (18π+7π)/30
=25π/30
so sin( 25π/30) = -1%2Fsqrt%282%29